Arena et al., WO94/12463, discloses the chemistry and pharmacology of nitroxybutylester[(CH.sub.2).sub.4 --ONO.sub.2 ] derivatives of several aryl propionic acid non-steroidal antiinflammatory drugs including ketoprofen, flurbiprofen, suprofen, indobufen and etodolac. Studies on nitroxybutylester derivatives of flurbiprofen and ketoprofen are also reported in Wallace et al., Gastroenterology, 107:173-179 (1994). See, also, Cuzzolin et al., Pharmacol. Res., 29(1):89-97 (1994); Reuter et al., Life Sci. (USA), 55/1(PL1-PL8) (1994); Reuter et al., Gastroenterology, 106(4):Suppl. A759 (1994); Wallace et al., Eur. J. Pharmacol., 257(3):249-255 (1994); Wallace et al., Gastroenterology, 106(4):Suppl. A208 (1994); and Conforti et al., Agents-Actions, 40(3-4):176-180 (1993). These publications uniformly examine and rely upon the use of indirectly linked nitrogen dioxide substitutions.